They are both about friendship and take place in the past, and they will also both give you this sentimental kind of feeling about growing up... and it will make you think about how important friends are! Def give it a go
If you'll like one then you'll definitely like the other! It's both about friends and has the same kind of humor, especially the slow motion fighting part resembles each other! Sunny is a bit more serious though :)
It gives the same kind of vibe... probably because both dramas have the same main actress but also because in both dramas they actually shouldn't be a couple because of their huge "differences". Watching Legend of The Blue Sea really reminds me of the time when I watched My Love From Another Star.